Influence of cooking methods on physicochemical characteristics and in vitro protein digestibility of restructured pork steak hydrolyzed by bromelain and reformed by κ-carrageenan

• The first study on bromelain and κ-carrageenan synergy in restructured pork steak quality with various cooking methods. • Sous vide cooking best preserves moisture, texture, and protein digestibility. • Bromelain enhances tenderness; κ-carrageenan stabilizes texture and prevents over-softening. • Cooking methods influence Maillard reactions, affecting color and water retention. • Protein digestibility improves with bromelain hydrolysis and controlled cooking techniques. This study systematically investigated the effects of cooking methods (sous vide, baking, and frying), enzymatic treatment with bromelain, and hydrocolloid stabilization using κ-carrageenan on the physicochemical properties and in vitro protein digestibility (IVPD) of restructured pork steaks. Sous vide cooking retained 36% more moisture (27% Water holding capacity; WHC) and had 84% lower cooking loss (4%) than fried samples, resulting in a more tender texture (hardness reduced by 30% compared to baked samples) and the highest IVPD (9% higher than baked and 10% higher than fried samples). Baked samples exhibited the highest WHC (42%), while fried samples showed the highest cooking loss (25%). Microstructure analysis revealed that sous vide samples maintained a more uniform and intact protein matrix, while fried samples exhibited greater structural disruption and porosity. Bromelain hydrolyzed muscle proteins into smaller peptides, improving tenderness and digestibility, while κ-carrageenan formed a stabilizing protein-polysaccharide network, counteracting bromelain's over-hydrolysis and preserving textural integrity. Additionally, κ-carrageenan significantly enhanced WHC and contributed to a uniform appearance across all cooking methods. This indicates that bromelain and κ-carrageenan work synergistically to enhance moisture retention, texture, and digestibility. Results demonstrate the potential of sous vide, combined with enzymatic and hydrocolloid treatments, to produce innovative, high-quality restructured meat products that align with modern consumer preferences for convenience, nutrition, and functionality. This research offers a promising framework for optimizing restructured meat production to meet evolving industry and consumer demands.